Low-cost high-efficiency solar membrane distillation for treatment of oil produced waters

摘要

Produced waters generated in oil industries are a significant issue of environmental concerns. Various physical, chemical, and biological methods are applied to treat produced waters. Membrane Distillation (MD) is a thermal-driven and vaporization-based technology that could be an ideal process for purifying produced water due to similar to 100% dissolved solids rejection, chemical-free mechanism, and low-energy requirements. Nanophotonics-Enhanced Solar Membrane Distillation (NESMD) is a novel type of MD operation which integrates photo-thermally active nanoparticles to provide localized water heating. The NESMD was investigated to treat oil produced waters. Commercial nanophotonics Polytetrafluoroethylene membranes containing polypropylene support layer were used. The experiments were carried out under different thermal and hydrodynamic conditions. In all the executed experiments, membrane hydrophobicity, measured as the contact angle and liquid entry pressure, was used to infer possible fouling of the membrane. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis were then employed to observe any morphological changes to the membrane, visualize possible organic fouling, and characterize the composition of mineral scales. The results showed that NESMD is a potential solution for the treatment of the produced water, with the overall dissolved organic carbon rejection ranging between 72.5% and 96%, and overall dissolved solid rejection higher than 99%.